The present invention relates to telecommunications cabling and devices for transmitting analog and digital electrical signals. In particular, the present invention relates to a modular cable system for providing data and voice communications to a plurality of workstations, which is easy to install and which reliably transmits the data at a high rate.
Communications cabling systems transmit information or data in the form of analog or digital electrical signals to and from various offices or workstations. Such cabling systems communicate between a distribution block or a patch panel located in a computer room or telecommunication closet and telecommunication devices located at the workstations, including telephones, facsimile machines and computers. Traditional cabling systems often comprise individual cables that extend uninterrupted from the wiring closet to the user devices (known as a xe2x80x9chome runxe2x80x9d cabling system). More recently, however, it has become increasingly popular to provide cabling systems with at least one connection point located intermediate the closet and the user devices (known as a xe2x80x9cmodularxe2x80x9d cabling system). A modular cabling system has the advantage in that moves, adds, and changes to the cabling system are substantially simplified in that there is no need to reconfigure the cables all the way back to the wiring closet. Instead, only the cables xe2x80x9cdownstreamxe2x80x9d of the intermediate connection point need be reconfigured. Despite the increasing popularity of modular cable systems, however, such modular cabling systems have several drawbacks.
One drawback with existing modular cabling systems is that they can be difficult or confusing for unskilled or inexperienced workers to install properly. This problem can be exacerbated when the modular cabling systems includes what will herein be referred to as Y-cable assemblies, which are another recent development. Each Y-cable assembly includes wiring for multiple offices or workstations and includes three connectors: one upstream connector, one downstream (or pass-thru) connector, and one extractor (or peel-off) connector. The upstream and downstream connectors of the Y-cables can be interconnected to one another to provide a segmented (or serially connected) cabling system that includes all the wiring necessary for the individual offices or workstations. Each Y-cable assembly in the serial chain extracts a unique subset of the wires (or a circuit) to its extractor connector for use by one particular office or workstation. Thus, it is important for the installer to be able easily distinguish the different Y-cables because each can be used only once in the same serial chain.
However, in prior art segmented cabling systems the unique Y-cables have been distinguished only by a part number, usually stamped on one of the connectors. This makes it difficult for the installer to ensure that the system is configured correctly, e.g., the part numbers must be either memorized or written down before comparing one Y-cable with another. Moreover, performing moves, adds or changes on an existing system is further complicated in that such part numbers are located on portions of the connectors that are not visible when the Y-cables are installed. As a result, the installer must either uninstall (at least partially) each of the Y-cables for purposes of identification, or the written records (if they exist) of the wiring scheme must be located and consulted.
Another drawback with existing modular cabling systems is that, although the cables may be capable of communicating at Category 5 or higher performance levels, the connectors often form weak points that limit the overall capabilities of the system. In particular, cross-talk, which is a measure of the amount of signal coupling occurring between different pairs of wires either in a cable or cable-to-cable, can be a problem in connectors when the electrical pins extend close to one another and in parallel. Such cross-talk is a source of interference that degrades the ability of the system to transmit or receive signals, and can become particularly acute at high speeds. It has been discovered, however, that terminating the wire pairs at pin positions so as to leave empty (or unused) pins between the wire pairs can reduce this cross-talk in the connectors, which enables higher data transmission speeds. Nevertheless, with the continuing demand for even faster data transmission rates, there remains a need for cable assemblies that offer reduced cross-talk at even high transmission rates (e.g., 100 MHz to 300 MHz).
Modular segmented cabling systems similar to the type contemplated herein are shown in co-pending and commonly assigned U.S. patent application No. 09/163,886, filed Sep. 30, 1998, now U.S. Pat. No. 6,168,458 (xe2x80x9cthe ""886 applicationxe2x80x9d). The ""886 application shows a preferred embodiment of a modular cabling system for providing high speed data communication to a cluster of eight workstations. The segmented cabling system shown in the ""886 application includes a unique color coding scheme that enables an installer to properly configure the system by following a few easy to remember rules. Moreover, the ""886 application also discloses a device for reducing cross-talk in the connectors.
Workstations conventionally include a variety of equipment besides computers, many of which do not communicate at the same high speeds as modern day computers. For example, telephones, facsimile machines, and modems operate quite well on cabling capable of transmitting signals at lower speeds, such as Category 3. Moreover, most equipment of these types require only one or two wire pairs for communication, rather than four as with computers. Providing transmission capability for such equipment, therefore, either requires that a separate low speed cabling network must be installed or, alternatively, that some of the cabling designed for high speed transmission be used for lower speed transmission.
Accordingly, it would be desirable to provide a single modular cabling system that can be easily installed to provide not only high speed communications for computers, but also low-speed communications for other types of equipment. Moreover, it would also be desirable to provide such a system using integrated connectors that pass both types of signals because this would reduce connector congestion and simplify installation.
The present invention relates to a modular communications cable assembly comprising a first connector and a second connector, each having an elongated array of electrical contacts. A first plurality of wires arranged in twisted pairs is terminated to selected electrical contacts in each array in a predetermined pattern such that at least one electrical contact remains unterminated between adjacent pairs of the first plurality of wires to reduce cross-talk therebetween. In addition, a second plurality of wires arranged in twisted pairs is terminated to selected electrical contacts in each array in the predetermined pattern such that no electrical contact remains unterminated between at least some adjacent pairs of the second plurality of wires.
The present invention also relates to a modular communications cable assembly for providing a plurality of communication circuits to a cluster of workstations. The cable assembly comprises an upstream connector, at least one downstream connector, a plurality of high-speed cable segments, and at least one low-speed cable segment. Each high-speed cable segment contains a set of twisted wire pairs for high-speed communication and extends between the upstream connector and one of the at least one downstream connectors. The at least one low-speed cable segment extends between the upstream connector and one of the at least one downstream connectors. The at least one low-speed cable segment provides a plurality of sets of twisted wire pairs for low-speed communication. Each circuit comprises one set of twisted wire pairs from the high-speed cable segments and one set of twisted wire pairs from the at least one low-speed cable segment
The present invention further relates to a wiring arrangement for providing a plurality of communication circuits to a cluster of workstations. The wiring arrangement includes at least one modular cable assembly having a set of wires extending between a pair of connectors. The set of wires is grouped into disjoint wiring subsets that define the plurality of circuits. The wiring arrangement comprises a breakout assembly for linking the plurality of circuits to the cluster of workstations. The breakout assembly includes a body, an in-feed connector, and a plurality of breakout connectors associated with the in-feed connector. The breakout assembly also includes communications wiring connecting the in-feed connector with the associated breakout connectors such that each circuit is diverted from the in-feed connector to one of the associated breakout connectors.